Wiseacres believe that Johann Sebastian Bach just couldn’t have had the time to pen all the music that we ascribe to him.

The contract he had for the final quarter-century of his life as Kantor of St Thomas’ Church in Leipzig was itself eye-watering in its demands for a weekly output of music for services, let alone his teaching and training obligations.

So how did he do it? The answer is, through brilliant organisation and delegation to copyists – remember, everyone working by flickering candlelight when the days drew in. No wonder Bach, like Handel, developed eye-problems. They both had cataract operations from the same surgeon (no anaesthetic).

And often part of JSB’s hardworking team were his own sons, themselves scions of an awesome musical dynasty which had begun long before their father’s birth. Today we remember mainly two of them, Carl Philipp Emanuel (the second son) and Johann Christian (the youngest).

Two upcoming concerts highlight their work, on March 31 at the Town Hall, Thomas Trotter plays a lunchtime organ recital celebrating the 300th birthday of Carl Philipp Emanuel Bach. Among the works on offer are a Fugue on BACH (a musical code using the notes B-flat, A, C and B-natural in German nomenclature); Carl’s father had already sown the seeds for such a resource.

Before that, Birmingham University’s Chamber Orchestra is conducted by Professor Andrew Kirkman, Christine Whiffen the harpsichord soloist, in works by CPE, JC and two other Bach sons (Wilhelm Friedmann and Johann Christoph Friedrich) at the Bramall Music Building on Sunday (3pm).

Carl was probably the most influential of Johann Sebastian’s offspring, perhaps remembered chiefly today for his magisterial textbook, The True Art of Playing Keyboard Instruments, valuable not only as a primer, but also as a guide to performance practice of the mid-18th century.

He was also harpsichordist to Frederick the Great at his court of Sans Souci in Potsdam. This was an amazingly cultured environment, created by the enthusiasm of Frederick himself for the arts, philosophy and so much else (as well as military strategy).

Johann Sebastian paid a visit to his son, and played before the King, who then offered him a musical theme upon which to improvise a fugue, which of course Bach did to great acclaim.

But, dissatisfied with his own efforts, on his return home to Leipzig, JSB set to compile the mind-bogglingly compendious Musical Offering, in which he subjects Frederick’s little theme to the most rigorous academic treatment in a variety of forms. Needless to say, Frederick was thrilled and flattered to receive the work.

Johann Christian Bach went in an entirely different direction. No confining aristocratic patronage for him. Instead he went to glamorous musical centres, first to Milan, and then to London, where he founded an important series of concerts with his colleague Carl Abel.

These were first held at Carlisle House in Soho Square, before moving to King Street, St James’s, and throughout this period Johann Christian was involved in composing operas and various other theatrical entertainments for venues such as the King’s Theatre and the Theatre Royal, Covent Garden.

And June 2, 1768, he gave a concert at the Thatched House Tavern in St James’s Street, where he played a solo on the piano forte – the first time that the piano was publicly used as a solo instrument in London.

But before then Johann Christian Bach had made probably his greatest contribution to musical history, when in 1762 he met and mentored the six-year-old Mozart.

The entire Mozart family was on a grand tour of Europe with an eye to cashing in on the child-wonder musical skills of Wolfgang and his older sister Nannerl, and they spent over a year in England, based in Chelsea, a stay perhaps extended by illness in the family.

Wolfgang learnt at Johann Christian’s knee the textures of piano-concerto composition, as well as how to launch a symphony: two bars of masculine directness, followed by two bars of yielding femininity (just listen to the opening of the Jupiter Symphony).

The two caught up with each other again many years later in Paris, Johann Christian nearing the end of his life, Mozart soon to be introduced on his imminent move to Vienna to the grandeur of Johann Sebastian Bach himself.

So the influence of Johann Sebastian Bach persisted long beyond that great man’s death. We can even feel it in the ether of Birmingham Town Hall, graced on so many occasions by Felix Mendelssohn, who had himself fallen under the spell of the old Leipzig master, the city where they had both lived.

* For more details on the University Chamber Orchestra ring 0121 414 3280, and for details of the Thomas Trotter recital ring 0121 780 3333.